Cell morphology of exposed cells. Illustrated pictures represent unexposed, 278 ng/cm2 Ag-NP and 22 mM AgNO3 exposed triple cell co-cultures. At 24 h after exposure, the cells were fixed and stained for the actin cytoskeleton (phalloidin rhodamine; red) and DNA (DAPI; blue). Examples of morphological changes in form of augmented DNA condensation and alterations in the cytoskeleton were marked with yellow arrows. Images for the actin cytoskeleton and nuclei on the left side are represented as single optical xy projections with representative side views in xz (bottom) and yz (left) direction. Nuclei on the right side are visualized by surface rendering of xy stacks (scale bar = 30 μm).